Exceptions names list

[Ali Çehreli]

On 11/16/21 12:30 AM, bauss wrote:
 > On Monday, 15 November 2021 at 22:44:35 UTC, Ali Çehreli wrote:
 >> On 11/15/21 2:28 PM, pascal111 wrote:
 >> > I want to know where the list of exceptions names that
 >> "throw" statement
 >> > uses.
 >>
 >> Such a list is not very useful. Normally all we need is Exception and
 >> occasionally one or two other specific types.
 >>
 >
 > It's actually very useful when you want to throw exceptions yourself,

That's very different from how I use exceptions perhaps because mine 
have been command line tools. I would love to learn more about how 
others use exceptions.

The existing exception type that I reuse is Exception :), which I throw 
indirectly by enforce:

   enforce(isOk, format!"There is a problem with %s"(x));

I even convert a ConvException that I catch to Exception with the same 
method just to give a little bit of more

   catch (ConvException ex) {
     enforce(false,
       format!"Failed to parse '%s' as blah: %s"(y, ex.msg));
   }

That shows how lazy I am. :)

 > because instead of writing your own custom exception then you could use
 > an existing implementation.

Unless there are standardized exceptions, that feels weird to me because 
such reused exceptions may have constructor parameters which may not 
make sense where I throw that exception.

Luckily, there is basicExceptionCtors, which trivializes implementing 
exception types anyway. For example, I copied the following from 
/usr/include/dmd/phobos/std/conv.d:

class ConvException : Exception
{
     import std.exception : basicExceptionCtors;
     ///
     mixin basicExceptionCtors;
}

Further, it doesn't feel right to throw e.g. std.conv.ConvException from 
my foo.bar module. The cases where another module's exception fitting my 
use closely feels so rare that I wouldn't even think about reaching for 
an existing exception of another module or a library.

I don't know... That's my comfortable and lazy use of exceptions. :)

Ali